Glass jar handling system

ABSTRACT

A system for use in depalletizing glass jars disposed in groups in a vertical stack wherein the groups of jars are successively moved laterally off the top of the stack and onto a lateral conveyor. The jars are supported on flat panels and a sensor is provided to sense the uppermost panel and to control the elevation of the stack, whereby the elevation will stop when the upper group of jars is aligned with the conveyor. Means is provided to push the jars away from alignment with the sensor so that it will engage the uppermost jar-supporting panel rather than the jars themselves. Means is also provided to push the upper panel laterally to assure that it will be in position to engage the sensor.

United States Patent 1 Nelson Jan. 15, 1974 GLASS JAR HANDLING SYSTEMPrimary Examiner-Robert G. Sheridan Assistant Examiner-George F. Abraham[75] Inventor. Lloyd A. Nelson, l remont, Mich. Atmmey ,rhomas F Smegal,Jr [73] Assignee: Gerber Products Company,

Fremont, Mich. ABSTRACT [22] Filed: 1972 A system for use indepalletizing glass jars disposed in [2]] Appl. No.: 306,269 groups in avertical stack wherein the groups of jars a are successively movedlaterally off the top of the Related US. Application Data stack and ontoa lateral conveyor. The jars are sup- [62] Division ofSer. No.173,887,Aug. 2s, 1971,Pat. No. pmed flat Panels and a Sens is pmvidedsense the uppermost panel and to control the elevation of the stack,whereby the elevation will stop when the 2 I I n upper group of jars isaligned with the conveyor. E2 1 E S I Means is provided to push the jarsaway from align- [58] Field of Search 2l4/8.5 A, 8.5 F Y the that engageupper 214/152 most ar-supporting panel rather than the ars themselves.Means is also provided to push the upper panel 56] References Citedlzteersilrlgglo assure that it will be in position to engage UNITEDSTATES PATENTS I 3,107,794 l0/l963 Bechtold 2l4/8.5 A 3,l80,499 4/l965Wildheim 214/85 A 3 Claims, 10 Drawing Figures PAIENTEBJAN 1 5 m4 saw 1OF 6 PATENTEDJAN 519M SHEE 3 1]? 6 GLASS JAR HANDLING SYSTEM Thisapplication is a division of application Ser. No. 173,887, filed Aug.23, 1971, which has matured into U.S. Pat. No. 3,724,686.

This invention relates to improvements in the handling of glass jars involume and, more particularly, to a system for separating stacked groupsof glass jars from a pallet.

Prepared baby foods are oftentimes packaged in relatively small glassjars of various volumes, representative volumes being denoted by 3% oz.,oz., 6% oz., and 8 oz. In a jar-filling operation, many such glass jarsmust be readied for use. A preferred way of handling the jars andtransporting them to a filling plant is to place groups of jars on anumber of panel dividers and to stack the jar-laden dividers on aconventional pallet. For instance, for a 5 oz. jar, there would be 483jars on each panel divider and 26 layers or groups of jars can bedisposed on a pallet. Therefore, each pallet would support 12,558 jarsand 16 such pallets can be placed in a van for moving the jars to thefilling plant. Thus, the van can carry a total of 200,928 jars. It canbe seen, therefore, that many jars are actually transported to a fillingplant. I

Conventional systems for handling pallets of such jars have been made tocause the groups of jars to be moved successively and incrementallyupwardly so that the top group of jars in a stack can be moved laterallyonto a conveyor. Thus, each group ofjars can be moved onto a dischargeconveyor as its panel divider is aligned with the conveyor.

To stop the uppermost panel divider in alignment with the conveyor,conventional equipment has a sensor which projects into the path of thepanel divider and engages its upper surface. The sensor serves toactuate a switch which controls the elevator drive for the pallet. Theproblem which arises, however, with the use of this sensor is that itoftentimes engages the jars on the uppermost panel divider rather thanthe divider itself. Thus, the panel divider stops below the conveyorrather than in alignment with it.

The present invention provides an improvement for such depalletizingequipment by providing means for assuring that'none of the jars on theuppermost divider panel engage the sensor as the pallet is incrementallyelevated. This is accomplished by moving certain jars out of alignmentwith the sensor, leaving the adjacent upper surface portion of theuppermost panel divider free to be engaged by the sensor. Thus, thesensor will sense the panel divider to effect the stopping of theelevation of the pallet so that the uppermost jars can be sweptlaterally off the divider and onto the discharge conveyor. Then, anoperator can lift off the uppermost panel divider, following which thenext incremental elevation of the pallet can occur.

Another aspect of the invention is to provide one or more pusher armsfor pushing a panel divider near the top of the stack laterally througha sufficient distance to assure that the panel divider will be inposition to be engaged by the sensing finger. This is necessary becausethe panel dividers on a pallet may not be truly vertically aligned witheach other and must be properly oriented to engage the sensor.Otherwise, the elevation may not stop when the uppermost panel divideris aligned with the discharge conveyor.

The primary object of this invention is to provide an I improved jarhandling system of the type having de palletizing capabilities includinga sensor for engaging the uppermost panel divider supporting one of agroup of vertically stacked jars on a vertically movable pallet. Meansis provided to move the jars on the uppermost panel divider to clear theupper surface portion thereof which is aligned with the sensor so thatthe latter will engage the uppermost panel divider rather than the jarsthemselves to effect the stopping of the elevation of the panel at alocation permitting the uppermost jars to be moved onto a lateralconveyor aligned with the uppermost divider.

A further object of this invention is to provide a system of the typedescribed wherein each panel divider is pushed laterally and against anabutment before it becomes aligned with the discharge conveyor so thatthe panel divider will be aligned with the sensor to engage the same asthe pallet is incrementally elevated.

Other objects of this invention will become apparent as the followingspecification progresses, reference being had to the accompanyingdrawings for an illustration of the invention.

IN THE DRAWINGS:

FIG. 1 is a side elevational view ofajar handling system including anelevator for a pallet containing stacked layers of jars, a lateraldischarge conveyor near the upper end of the elevator and a pusher armfor sweeping the uppermost layer of glass jars in the stack onto thetakeoff conveyor;

FIG. 2 is a top plan view of the system of FIG. 1;

FIG. 3 is an enlarged, fragmentary top plan view of a sensing finger tosense the panel divider supporting the uppermost layer of glass jars;

FIG. 4 is a fragmentary front elevational view of the jar shiftingmechanism below the sensing finger of FIG.

FIG. 5 is a side elevational view of the mechanism of FIG. 4, showingthe operative and retracted positions thereof;

FIG. 6 is a view similar to FIG. 3 but showing the retracted position ofthe mechanism of FIGS. 4 and 5;

FIG. 7 is a view similar to FIG. 6 but showing the jar shifting positionof the mechanism;

FIG. 8 is a schematic view of the portion of the system near the upperend of the elevator, showing the jar shifting mechanism and a device forshifting a panel divider toward the shifting mechanism;

FIG. 9 is an enlarged, fragmentary side elevational view of the pushermechanism; and

FIG. 10 is a rear elevational view of the pusher mechanism.

The glass jar handling system with which the improvements of the presentinvention are utilized is of the type shown in FIG. 1 and includes afirst infeed conveyor 10, a second, relatively short conveyor 12 alignedwith infeed conveyor 10 and disposed at the bottom of an elevator bin 14having a front wall 16 and a rear opening 18 extending upwardly frombelow the planes of conveyors l0 and 12 to a backstop l9 hereinafterdescribed. A pair of outwardly flared side strips 21 (FIGS. 1 and 2)embrace opening 18 and serve to funnel an incoming stack of jars on apallet advanced toward conveyor 12 by conveyor 1a.

A discharge conveyor 20 is adjacent to and projects laterally from theupper end of elevator bin 14, and a second discharge take-away conveyor22 is horizontally aligned with conveyor 20 but extends at right an glesthereto. An elevating mechanism 13 shown only partially in FIG. 1,operates in bin 14 to move incrementally upwardly so that a palletcontaining vertically stacked groups of jars on mechanism can be movedupwardly, in stepwise fashion, mechanism 13 stopping each time theuppermost group ofjars can be swept laterally onto conveyor 20 by sweeparm means 24. When all of the jars have been removed in this manner fromthe pallet, mechanism 13 is lowered and thus returns it to its initialposition shown in FIG. 1 in horizontal alignment with infeed conveyor10.

The system thus described is adapted to be utilized to depalletize glassjars 25 (FIG. 2) disposed in stacked layers on a conventional pallet,each layer of glass jars being disposed and supported on a panel divider26 (FIG. 3, 7 and 8) with each divider being supported by the layer ofglass jars therebelow and the lowermost divider supported on the palletitself. The pallet with the stackof glass jars thereon can be loaded oninfeed conveyor 10 in any suitable manner, conveyor 10 being operated toadvance the loaded pallet toward and onto elevator bin conveyor 12,whereupon the pallet is incrementally elevated to successively positionthe uppermost layers of glass jars in position to be swept laterally andonto discharge conveyor 'as the divider panel for the uppermost jarsremains in the bin. The divider panel at the uppermost level can then bemanually lifted off the stack by an operator, following which theelevating conveyor can move again through the incremental distancenecessary to advance the various layers of jars successively intohorizontal alignment with conveyor 20.

The elevation of mechanism 13 is operator controlled and the operatorcan observe when the upper layer of glass jars has been swept ontoconveyor 20. He can then actuate the power means of mechanism 13 forelevating the latter once again. Sweep arm means 24 has a laterallyshiftable sweep arm plate 28 coupled in any suitable manner tofluid-actuated power structure 30 (FIG. 8) which reciprocates the platefrom right to left and then the plate is returned to the right whenviewing FIG. 8.

When the empty pallet is lowered, it is brought into horizontalalignment with an empty pallet discharge conveyor 32 (FIG. 1) and thelatter conveyor advances the same to a side transfer mechanism (notshown) then into an empty pallet stacker for stacking in an orderlyfashion. As an empty pallet moves to the left when viewing FIG. 1 ontoconveyor 32, a loaded pallet with glass jars thereon can be moved frominfeed conveyor 10 onto elevator bin conveyor 12 to prepare for the nextdepalletizing operation.

The system thus far described utilizes one or more sensors 34 near theupper end of elevator bin 14. The purpose of each sensor is to sense theupper surface of the uppermost divider 26 and, since the sensor is inhorizontal alignment with the upper stretch of discharge conveyor 20, itfollows that the uppermost divider panel, when it is sensed by thesensor, will also be in horizontal alignment with the upper stretch ofdischarge conveyor 20. Sensor 34 is coupled mechanically by a shaft 36to a limit switch 38 (FIG. 4 and 5), the limit switch being operable tocontrol a hydraulic circuit which gages travel of mechanism 13. Thesensor is slightly movable upwardly so that the limit switch is actuatedto de-energize mechanism 13 and to stop its elevation when the uppermostdivider panel is in horizontal alignment with the upper stretch ofconveyor 20. Then, the operator actuates power structure 30 causingsweep arm plate 28 to sweep the jars on the uppermost divider 26laterally and onto a discharge conveyor 20.

It has been found that the jars on the uppermost divider panel maysometimes engage sensor 34 during the elevation of the uppermost layer,and when this occurs, the sensor is shifted upwardly to cause prematuredeactuation of the hoist. This will occur, of course, before the divideris horizontally aligned with the upper stretch of conveyor 20. To avoidthis problem, one of the improvements of the present invention providesa jar shifting mechanism 40 (FIGS. 4-7) which includes a jar shiftingmember 42 mounted on the upper end of an arm 44 whose lower end ispivotally mounted by bearing 46 on a generally horizontal shaft 48rigidly secured by mounts 50 in any suitable manner to the adjacentfront wall 16 defining a part of elevator bin 14. Arm 44 has a lateralextension 52 (FIG. 5) secured to its lower end, extension 52 projectingaway from shaft 48. The outer end of extension 52 has a clevis 54 whichis coupled to the outer end ofa piston rod 56 of a fluid piston andcylinder assembly 58. The opposite end of the cylinder 60 of assembly 58is pivotally secured by a pin 62 on structure 64 also rigid to frontwall 16. Actuation of assembly 58 causes the piston rod 56 to moveoutwardly of cylinder 60 and this causes the cylinder to pivot about pin62 from the full line position of FIG. 5 to the dashed line positionthereof. This causes extension 52 and thereby arm 44 to pivot aboutshaft 50, causing member 42 to move from the right hand side (FIG. 5) ofwall 16 through an opening 66 therein to the lefthand side as shown indashed lines in FIG. 5.

As member 42 moves in the foregoing manner, it moves any jars in itspath away from the adjacent edge of the corresponding divider 26, thusleaving a portion of the upper surface of the divider clear of any jars.As shown in FIG. 3, member 42 is directly below sensor 34 so that thecleared portion of the upper surface of the uppermost divider 26 willengage the sensor as the divider is elevated by mechanism 13.

Member 42 has a convex outer surface 68 as shown in FIGS. 3, 4, 6 and 7to facilitate movement of the adjacent jars. Also, the vertical lengthof member 42 is short enough to prevent it from engaging the divider asit shoves the jars inwardly of the adjacent edge of the divider. Thisassures that member 42 will not be stopped prematurely before the jarshave been move through the proper distance.

Means is provided adjacent to elevator bin 14 to shove one or more ofthe upper dividers 26 to the left when viewing FIGS. 1 and 8 or towardand into engagement with front wall 16. The purpose of this feature isto assure that the uppermost divider is sufficiently close to front wall16 such that an upper surface portion of the uppermost divider will bevertically aligned with sensor 34. Oftentimes the various dividers inthe stack on the pallet are not in true vertical alignment with eachother. Also, some dividers may be too far from wall 16 to permit them toengage the sensor.

To avoid this problem, a number of pusher bars 70 are mounted forpivotal movement on backstop 19 near the upper end of elevator bin 14 asshown in FIGS. 8-10. Each bar 70 has an offset extension 72 (FIGS. 9 and10) which is rigidly secured to a shaft 74 mounted by a number ofbearings 76 on the rear face of backstop 19. One of the bearings 76 isshown in FIGS. 9 and 10. Backstop 19 has openings 78 therein for pusherbars 70, respectively, to permit the bar to extend into bin 14. Thewidth of each bar is such as to cause it to extend a distance into bin14 sufficient to engage and push an adjacent divider 26 toward andagainst front wall 16. Thus, this wall acts as an abutment to limit thehorizontal movement of the divider.

The pusher bars 70 are moved simultaneously by the rotation of shaft 74through a small are under the influence of a double actingfluid-actuated power assembly 80. To this end, assembly 80 has acylinder 82, one end of which is pivotally coupled by a pin 84 to therear face of backstop 19. A piston within the cylinder has a rod 86which projects outwardly from the cylinder and is pivotally coupled by apin 88 to one end of an arm 90 whose opposite end is rigidly secured toshaft 74. Thus, when rod 86 is forced into cylinder 82, the effectivelength of assembly 80 decreases, thereby causing shaft 74 to rotate in acounterclockwise sense. This causes pusher bars 70 to movesimultaneously through respective opening 78 and against the adjacentedge of a divider 26 to urge the latter toward and into engagement withfront wall 16. When rod 86 moves outwardly of cylinder 82, shaft 74 isrotated in a clockwise direction to cause the pusher bars to retract. Tolimit the rearward movement of the pusher bars when the same areretracted, backstop 19 has a rear overhang 92 (FIG. provided with aninclined rear extension 94 in the path of the upper end of each pusherbar 80. Also, to limit the forward travel of the pusher bars, each bar70 has a rear plate 96 thereon for engaging the rear face of backstop 19when the bar has moved through the desired maximum distance into bin 14..Thus, plates 96 serve as stops. Generally, pusher bars 70 will beoperable to engage and push the divider second from the top. However,more than one divider can be pushed, if desired.

FIG. 8 illustrates in a schematic form the fluid source 98 for supplyingfluid under pressure to power devices 30, 58 and 80. Source 98 iscontrolled by the operator of the system which includes a pump 100 and avalve 102 for controlling fluid under pressure emanating from a fluidtank 104. Source 98 is controlled in a manner such that fluid issupplied to power devices 58 and 80 simultaneously to cause inwardmovements of member 42 and pusher bars 70. Also, member 42 and thepusher bars are retracted at the same time.

OPERATION The system is placed in operation when a full pallet is placedon in-feed conveyor 10. Such a pallet may contain 26 layers of glassjars to be unloaded or depalletized. Conveyor 10 is advanced under the control of the operator of the system and additional pallets can beplaced several feet apart on this conveyor.

As the conveyor advances, the lead pallet enters elevator bin 14.Sometimes, a full pallet of jars may be slightly out of perpendicularand, to offset this problem, bin 14 may have side plates whichstraighten the stack as it enters bin 14. The full pallet, when'completely in bin 14, engages front wall 16 and is halted thereby. Asthe pallet enters the bin, member 42 and the pusher bars are in theirretracted positions. Also, plate 28 is in its retracted position shownin FIG. 8. Divider 26 will be on the top of the full stack. Thus, whenmechanism 13 is energized, this top divider will engage sensor 34,causing the latter to stop the mechanism, whereupon the operator thenactuates source 98 to effect the movement of member 42 and the pusherbars into bin 14. Member 42 moves the adjacent jars 25 to clear aportion of the upper surface of the divider of the first layer of jars.Simultaneously, the pusher bars move the last-mentioned divider againstthe inner face of front wall 16. Simultaneously with these actions,plate 28 is swept over the top divider and then returned to itsretracted position. As plate 28 is retracted, member 42 and the pusherbars are also retracted. The top divider is then manually removed andplaced on an accumulation conveyor (not shown) for movement away fromthe top of the bin.

The operator then actuates mechanism 13 to elevate the pallet until thetop divider engages sensor 34. This causes the elevation to stop and theoperator actuates source 98 to again effect inward movement of member 42and pusher bars for the same purpose as mentioned above. Simultaneouslywith these actions, plate 28 sweeps the uppermost layer of jarslaterally and onto conveyor 20, there being a bridging or dead plate(not shown) between the upper stretch of the conveyor and the upperdivider 26. The jars on the second layer are pushed inwardly by member42 and the second divider is forced toward wall 16. As plate 28 isretracted, member 42 and the pusher bars are retracted also. Theforegoing steps are repeated until the pallet is in the second layerposition at which time the power devices 58 and are overpowered by thepallet, signalling to the operator that the jars have all been removedfrom the pallet. Mechanism 13 is then lowered until it is at the bottomend of its path of travel. Conveyors l0 and 12 are then simultaneouslyactuated, the empty pallet moving onto discharge conveyor 32 and a fullpallet moving onto conveyor 12 from conveyor 10. The foregoing processcan be continued until all of the full pallets have been unloaded. Also,the collection of the empty pallets can be such that they are returnedto a station from which they can be loaded onto the van and returned tothe loading plant.

In the claims:

1. A method of unloading a plurality of articles arranged in layers onrespective panel dividers disposed ina vertical stack comprising:elevating said stack; sensing an upper surface portion of the uppermostdivider when the stack has been elevated through an incrementaldistance; stopping the elevation of the stack when the uppermost divideris sensed, sweeping the articles on the uppermost divider off the samewhen the elevation of the stack has been stopped; moving certain of thejars on a second divider to expose an upper surface portion thereof, andto permit the latter to be sensed when the stack is again moved throughsaid incremental distance; and successively repeating said elevating,sensing, stopping, sweeping and moving steps until all of the articleshave been swept off their respective dividers.

2. A method as set forth in claim 1, wherein said sweeping and movingsteps occur simultaneously.

3. A method as set forth in claim 1, wherein is included the step ofpushing the second divider along a horizontal path and through adistance to assure that it will be sensed when it becomes the uppermostdivider.

1. A method of unloading a plurality of articles arranged in layers onrespective panel dividers disposed in a vertical stack comprising:elevating said stack; sensing an upper surface portion of the uppermostdivider when the stack has been elevated through an incrementaldistance; stopping the elevation of the stack when the uppermost divideris sensed; sweeping the articles on the uppermost divider off the samewhen the elevation of the stack has been stopped; moving certain of thejars on a second divider to expose an upper surface portion thereof, andto permit the latter to be sensed when the stack is again moved throughsaid incremental distance; and successively repeating said elevating,sensing, stopping, sweeping and moving steps until all of the articleshave been swept off their respective dividers.
 2. A method as set forthin claim 1, wherein said sweeping and moving steps occur simultaneously.3. A method as set forth in claim 1, wherein is included the step ofpushing the second divider along a horizontal path and through adistance to assure that it will be sensed when it becomes the uppermostdivider.